As the number of user devices or stations (STAs) with WiFi connection capability (e.g., smartphones/tablet computers) keeps on increasing, the density of access points (APs) as well as STAs is getting higher, such as instance in growing urban areas. Since the original design for WiFi systems assumes a low density of APs and STAs, the high density of APs and STAs can make the WiFi system less efficient. For example, the current enhanced distributed channel access (EDCA)-based media access control (MAC) scheme for wireless communications may not work efficiently in an environment with a high density of APs and STAs. Therefore, there is a need for a scheme to improve wireless system performance, such as in high density WiFi environments.